In many instances involving hot water heating systems, sections of the systems, especially those located far from the boiler, may be exposed to freezing conditions because the thermostat which controls the water circulation is installed in a well-insulated area while the vulnerable sections are not. Typical examples include a renovated dwelling with new thermal insulation where heating conduits have been left between the insulation layer and the outside walls, and/or heating conduits running along door and window frames.
Similarly, in dwellings that are not occupied for long periods during the cold season, where draining a heating system or using glycol is not practicable and maintaining the place warm to prevent conduit freezing does not justify increased fuel expenses and air pollution, for example, sections of the heating system can freeze.
Freezing of one or more portions of a heating system can result in pipe cracks and pipe joint failures, which can lead to water damage and significant expense.
A variety of methods have been employed to prevent pipe-freeze damage from happening. One such method is to wrap electric heating wire around the pipe. The wire conducts current and heats-up when the pipe temperature gets near the freezing point. Disadvantages of this method include installation difficulties and electrical energy consumption. Other methods require installation of special valves and/or other mechanical plumbing devices. Disadvantages of these alternatives are the cost of the additional devices and required installation.